As a full-face-type helmet having a ventilator mechanism in its head protecting body for the purpose of ventilation of the interior of the head protecting body or fogging prevention of the inner surface of a shield plate, for example, one described in U.S. Pat. No. 5,093,938 is conventionally known.
The full-face-type helmet (to be merely referred to as “the conventional helmet” hereinafter). described in U.S. Pat. No. 5,093,938 has a forehead ventilator mechanism and chin ventilator mechanism above and under a window opening, which is formed in a full-face-type head protecting body to be worn on the head of the wearer, to oppose the face of the wearer. The forehead ventilator mechanism and chin ventilator mechanism have a forehead air supply hole and chin air supply hole, respectively. The forehead and chin air supply holes can be opened/closed by a forehead shutter member and chin shutter member, respectively.
Hence, in the conventional helmet, when the forehead air supply hole is opened, the outer air can be introduced into the head protecting body (i.e., the internal texture of the head protecting body itself and/or the head accommodating space of the head protecting body), to perform ventilation of the interior of the head protecting body. When the chin air supply hole is opened and the outer air is introduced into the head protecting body near the lower end of the inner surface of the shield plate, the introduced outer air moves up along the inner surface of the shield plate, to prevent fogging of the shield plate.
In the conventional helmet with the above arrangement, however, the outer air introduced into the head protecting body through the forehead air supply hole merely diffuses naturally over a wide range in the head protecting body, and draft for ventilation of the interior of the head protecting body and the like cannot be performed effectively. The outer air introduced into the head protecting body near the lower end of the inner surface of the shield plate through the chin air supply hole not only drifts upward along the inner surface of the shield plate, but its considerable portion naturally diffuses over a wide range in the head protecting body. Thus, fogging of the shield plate cannot be prevented well.
Therefore, with the conventional helmet, when it rains and the humidity is very high, ventilation of the interior of the head protecting body and fogging prevention of the shield plate cannot be performed effectively.
The present invention aims at effectively correcting the drawbacks of the conventional helmet described above with a comparatively simple arrangement.